In June 2012 the German Federal Joint Committee (G-BA), the national reimbursement authority, determined that Sativex provides added benefit over current treatment options in the treatment of spasticity in multiple sclerosis (MS). The next step in the process has been for Almirall to negotiate a price for Sativex with the German National Association of Statutory Health Insurance Funds. After several months of inconclusive discussions, Almirall recently attended a meeting with an arbitration board. The outcome of this meeting, which was communicated to Almirall today, was the determination of a price significantly lower than the reimbursed Sativex price in other European countries. Sativex is one of several recent examples of new medicines that have not been appropriately valued by the new German reimbursement system.

The decision in Germany is in distinct contrast to the price agreed in every other European country to date, where pricing reflects the value that Sativex brings to patients with an unmet need. Our partners, Almirall, consider the German price to be unacceptable and plan to take all necessary steps to challenge the decision, which may include suspension or withdrawal of supply in Germany, whilst they pursue a reasonable solution. Almirall is committed to maintaining the success and value of the Sativex franchise across Europe.

Sativex is now approved in 20 countries, in eight of which commercialisation has now commenced - UK, Spain, Germany, Denmark, Norway, Sweden, Canada and Israel. The 12 additional countries in which Sativex has received regulatory approval are Austria, Czech Republic, Belgium, Finland, Iceland, the Netherlands, Luxembourg, Poland, Portugal, Slovakia, New Zealand and Australia. Launches in most of these countries are expected to take place in the next twelve months. In addition to the 20 countries which have formally approved, we are awaiting product licences in two further countries (Italy and Ireland) that have recommended approval. Regulatory applications have also been submitted in Switzerland and seven countries in the Middle East.

“Sativex has an excellent record of achieving appropriate price levels in all other countries to date and we are confident that the ongoing global commercial prospects for Sativex outside of Germany are unchanged,” stated Justin Gover, GW‘s Chief Executive Officer. “The recently introduced pricing and reimbursement system in Germany has been presented as a means of recognising innovative new medicines that provide added value over existing treatment options. Despite Sativex being a clear example of such a medicine, as recognised in other markets, the German system appears to be neglecting the interests of patients and jeopardising pharmaceutical companies’ ability to provide German patients with access to new treatments. Sativex is one of several examples of new medicines that have not been appropriately valued by the German reimbursement system. Almirall is now taking all necessary steps to maintain the success and value of the Sativex franchise across Europe.”

Since the introduction of Sativex in mid-2011 it is estimated that approximately 3,000 German patients are currently receiving treatment with Sativex and this number has been growing steadily. Sativex treats patients with MS spasticity, who have failed to respond adequately to conventional anti-spasticity drugs. Sativex helps patients who are often significantly hindered in their day-to-day lives by MS-induced spasticity to partially regain their mobility, freedom and quality of life.

“The new price decision in Germany is inappropriate for an innovative treatment option for severely suffering patients who currently do not have other options and no longer covers the financing of the product. We will evaluate all possible options and further steps for Sativex as Almirall believes Germany should continue as a relevant country for innovative medicines”, stated Farid Taha, Managing Director of Almirall Hermal GmbH.

Sativex is the world’s first plant-derived cannabinoid prescription drug. In addition to MS spasticity, Sativex is also in Phase III clinical development as a potential treatment of pain in people with advanced cancer. The cancer pain indication represents the initial target indication for Sativex in the United States. In addition to Sativex, GW has a deep pipeline of additional cannabinoid product candidates, including two distinct compounds, GWP42004 and GWP42003, in Phase 2 clinical development for Type 2 diabetes and ulcerative colitis, respectively, and at least two additional programmes in epilepsy and glioma expected to enter clinical trials in the next 12 months.

For GW’s financial year ended 30 September 2013, we expect to account for a provision of £0.8 million to reflect the impact of this pricing decision, which we are required to apply to sales in Germany from July 2012, and product sales will be lower than previously expected. Cash and cash equivalents at 31 December 2012 was £27.6 million.

GW will make further announcements in relation to this development when appropriate.

Enquiries:

GW Pharmaceuticals plc

(Today) +44 20 7831 3113

(Thereafter) +44 1980 557000

+1 401 500 6570

Justin Gover, Chief Executive Officer

Stephen Schultz, VP Investor Relations

FTI Consulting

Ben Atwell / Simon Conway / John Dineen

+44 20 7831 3113

Peel Hunt LLP

James Steel / Vijay Barathan

+44 207 418 8900

About GW Pharmaceuticals plc

Founded in 1998, GW is biopharmaceutical company focused on discovering, developing and commercializing novel therapeutics from its proprietary cannabinoid product platform in a broad range of disease areas. GW commercialized the world’s first plant-derived cannabinoid prescription drug, Sativex, which is approved for the treatment of spasticity due to multiple sclerosis in 20 countries. Sativex is also in Phase 3 clinical development as a potential treatment of pain in people with advanced cancer. This Phase 3 program is intended to support the submission of a New Drug Application for Sativex in cancer pain with the U.S. Food and Drug Administration and in other markets around the world. GW has established a world leading position in the development of plant-derived cannabinoid therapeutics and has a deep pipeline of additional cannabinoid product candidates, including two distinct compounds, GWP42004 and GWP42003, in Phase 2 clinical development for Type 2 diabetes and ulcerative colitis, respectively, and at least two additional programs expected to enter clinical trials in the next 12 months. For more information, please visit the Company’s website at www.gwpharm.com

This news release may contain forward-looking statements that reflect GWs current expectations regarding future events, including development and regulatory clearance of the GW’s products. Forward-looking statements involve risks and uncertainties. Actual events could differ materially from those projected herein and depend on a number of factors, including (inter alia), the success of the GW’s research strategies, the applicability of the discoveries made therein, the successful and timely completion of uncertainties related to the regulatory process, and the acceptance of Sativex® and other products by consumer and medical professionals.